Print ribbon feed mechanism



`Iune 5, 1962 E. o. BLODGETT ETAL 3,037,448

PRINT RIBBON FEED MECHANISM 5 Sheets-Sheet 1 Filed March 28, 1961 xav Y ww mw INVENToRs EDWIN O. BLODGETT BY HAROLD F. STIFFLER @y ATTO RMEY June 5, 1962 E, o, BLODGETT ETAL 3,037,448

PRINT RIBBON FEED MECHANISM Filed March 28, 1961 5 Sheets-Sheet 2 Tia. E.

INVENTORS EDWIN o. BLODGETT BY HAROLD F. sTlFFLER Mig-iw I' ATTO RMEY June 5, 1962 E. o. BLoDGl-:TT ETAL 31,037,448

PRINT RIBBON FEED MECHANISM 5 Sheets-Sheet 3 Filed March 28, 1961 INVENTORS EDWIN O. BLODGETT HAROLD E STFFLER BY ,MM

ATTORNEY v June 5, 1962 E. o. BLODGETT ETAL 3,037,448

PRINT RIBBON FEED MECHANISM Filed March 28, 1961 5 Sheets-Sheet 4 INVENToRs EDWIN O. BLODGETT BY HAROLD E STIFFLER MQQ# ATTORNEY June 5, 1962 E. o. BLODGETT ETAL 3,037,448

PRINT RIBBON FEED MECHANISM Filed March 28, 1961 5 Sheets-Sheet 5 Tic.

INVENTORS EDWIN o. BLoDeETr BY HAROLD E snFFLER ATTORM 3,037,448 Patented June 5, 1962 ffice 3,037,448 PRINT RIBBUN FEED MECHANISM Edwin 0. Blodgett, Rochester, and Harold F. Stitier, Scottsvilie, N.Y., assignors to Commercial Controls Corporation, Rochester, N.Y., a corporation of Dela- Ware Filed Mar. 28, 1961, Ser. No. 98,964 4 Claims. (Cl. lOl-336) The present invention relates to ribbon feed mechanisms and, particularly, to ribbon feed mechanisms for a character printer structure.

It is an object of the invention to provide a new and improved print ribbon feed mechanism for a character printer.

It is a lfurther object of the invention to provide a novel print ribbon `feed mechanism in which a print ribbon is fed between two ribbon reels `and moves alternately and successively from one reel to the other with reversal of it-s direction of feed automatically effected near each end of the ribbon. by operation of an improved feed reversing structure.

lt is -an additional object of the invention to provide a print ribbon feed mechanism particularly suited for use with a character wire printer and one having a relatively sturdy yet low cost construction exhibiting high reliability of operation with minimized care and service attention over prolonged operational periods.

Other objects and advantages of the invention will appear as the detailed description thereof proceeds in the light of the drawings forming -a part of this application and in which:

FIG.1 illustrates in plan view a print ribbon feed mechanism embodying the present invention and constructed in assembly with a character wire printer structure and a tape punch structure;

FIG. 2 illustrates in end elevational view, and FIG. 3 in back elevational View, the FIG. l structure;

FIG. 4 is an elevational View illustrating more clearly the construction of the print ribbon feed mechanism of the present invention, FIG. 5 being a fragmentary plan View taken along the plane 5-5 of FIG. 4;

FIGS. 6 and 7 are fragmentary views illustrating two phases of the operation of the feed reversing structure utilized in the ribbon feed mechanism of the present invention; and

FIG. 8 is a fragmentary plan view illustrating the relative arrangement of certain feed reversing structural components in the position which they are shown as occupying in FIG. 7.

Referring now more particularly to FIGS. 1 3 of the drawings, a ribbon feed mechanism used with a character wire printer and embodying the present invention is conveniently constructed as an assembly fabricated with the wire printer upon a casting 10` aixed by machine screws (not shown) upon the back casting 11 of a unitary tape punch unit having the construction shown in FIGS. 8412 of the United States Blodgett Patent No. 2,927,158. The printer casting 10 is precisely positioned on the back casting 11 of the tape punch by lconventional use of locating pins, not shown.

As more fully shown and described in the Blodgett patent last mentioned, the tape punch also includes a front casting 12 iixedly secured in spaced relation to the back casting 111. The various components which make up the punch structure are supported on or between the back casting 11 and front casting 12, and brieiiy considered for purposes of the present description include a pin wheel 13 supported upon a shaft 14 and rotatable manually by a knob 15 or mechanically by a ratchet wheel and pawl 16 of which the pawl is reciprocated once during each punch cycle. A manually actuated hold down plate 17, pivotally supported upon the casting 11, permits tape to be manually placed in the punch and maintains the feed holes of the tape in engagement with the teeth of the pin wheel 13 to effect step by stepy movement of the tape past the punch die and punch pins positioned beneath a pl-astic housing 18 cooperating with a chute 18a to remove the punch chaff. The punch structure is mechanically driven through each of successive punch cycles by each complete rotation of a power shaft 19 connected through a exible coupling 20y and a cycle control clutch (not shown) to an electric drive motor. The power shaft 19 is journalled in ball bearing raceways supported by the casting 10 of the Wire printer assembly and by the front casting 12 of the punch assembly, and effects actuation o-f the punch pins under control of individual electromagnets supported within a frame 21 as more fully shown and described in the aforementioned Blodgett patent. Electrical connections to the electromagnets are effected through a plugboard 22 having paired receptacles in order that a common electrical connection may be made to an individual electromagnet within the frame 2|1 and to a corresponding individual electromagnet of the Wire printer which is disclosed and described more fully in the copending application Sea'. No. 98,963, filed March 28, 1961, entitled Character Wire Printer, and assigned to the same assignee as the present application.

The punch structure includes Aa top plate 23 over which the tape passes in its movement past the punch station. The printer includes a nose-shaped print wire guide 24 which has formed internally thereof a plurality of converging curvilinear channels through which individual ones of plural print wires are supported and guided into a cluster thereof at the print zone lying bneath the end 25 of the wire guide 24 which has a small spacing from a tape lying on the plate 23. As will presently be eX- plained more fully, a ribbon impregnated with printing ink or other suitable print medium is guided by rolls 26, 27, and 28 between supply and take up reels 29 and 30 and moves between the ends of the print wires and the upper surface of a tape moved step by step over the top surface of the plate 23. Characters are thus printed by the print wires on the upper surface of the tape in spaced relation to the punching of a corresponding binary coded character at the punch station of the punch unit.

The wire printer assembly is essentially comprised by three principal subassemblies: a code-plate retaining and actuating subassembly 34 which includes the print Wire guide 24, a code translator subassembly 35 for horizontally positioning the code plate of the subassembly 34, and a code translator subassembly 35 similar in construction to the translator subassembly 35 and operating vertically to position the code plate of the subassembly 34.

The printing ribbon transport assembly has the construction shown -in FIGS. 4-8 and is assembled on a casting 38 which is secured by machine screws and loeating pins (neither shown) to the casting 10 of the wire printer. Each of the ribbon supply and take up -reels 29 and 30 is removably supported by conventional spring detents (not shown) on stud shafts 39 journ-alled for rotation in the casting 38. The shafts 39 have integral reel support flanges 40 fixed to the shaft and Carrying pins 41 for engagement in an aperture of the reels 29 and 39 for positive drive thereof by respective ratchet wheels 43 and 44 also iixed to the shafts 39. The print-ing ribbon 45 extends from the reel 29 over the guide pulleys 26 and 27 and then is guided beneath a guide plate 46 slotted at 47 to receive the end 25 of the print wire guide 24. The end 48 of the guide plate 46 is turned over and slotted to receive and guide the printing ribbon. The guide plate 46 is retained by a knurled and slotted screw 49 on a bar 50 supported on the punch structure in spaced relation to the tape platform 23. The guide plate 46 has a handle 51 so that it may be manually grasped and moved to a forward position where the printing ribbon may be threaded under it after which it is repositioned and fixed in place on the bar 50 by the thumb screw 49. The bar 50 also supports a guide plate 52, which is secured to the bar by machine screw 53 and serves in conjunction with the guide plate 46 to guide the printing ribbon 45 from the printing Zone beneath the end of the Wire guide 24 past the guide roller 28 and onto the reel 30.

The printing ribbon is advanced step by step past the printing zone just preceding each printing operation. As explained more fully in the aforementioned Blodgett et al. application, the code translator subassemblies and 35' are reset by a reset lever 55 (FIG. 3) actuated by a cam 56 fixed to the drive shaft 19. The reset lever is fixed to a shaft 57, which is journalled in the casting 10 and is thus rotated by the reset lever and moves a crank arm 58 (FIG. 4) also fixed to the shaft 57. The arm 58 has a pin 59 which engages a slot 60 in a link member 61, a spring 62 extending between a pin 63 on the member 61 and a pin 64 on the casting 38 maintaining the pin 59 in contact with one end of the slot 60. The link member 61 is pivotally connected by a pin 65 to one arm of a bell crank 66 rotatably supported on a stud shaft 67 of the casting 38. The other arm of the bell crank 66 is connected through a pin 68 to a pawl 69 having 4a turned over end 70 bevelled to engage the teeth of either the ratchet wheel 44 or the ratchet wheel 43. An overcenter spring 71, extending between a pin 72 of the casting 38 and a pin 80 on the pawl 69, maintains the bevelled end of the pawl 69 in engagement either with the teeth of the ratchet wheel 44 or valternatively with the teeth of the ratchet wheel 43. A detent pawl 73 is pivotally supported on a stud shaft 74 of the casting 3S, has oppositely disposed side projections 75 and 76 turned over at their ends to anchor helical springs 77 and 78, and has an aperture 79 through which the pin 80 on the pawl 69 may extend to anchor the ends of both of the helical springs 77 and 78. The detent pawl 73 has a turned over end 83 bevelled to engage the teeth of either the ratchet wheel 44 or the ratchet wheel 43, and the interconnection by the springs 77 and 78 of the pawls 69 and 73 enables the overcenter spring 71 to maintain the bevelled ends of both pawls in engagement with the teeth of the ratchet wheel 44 or 43 while yet permitting relative longitudinal reciprocal movement of the pawl 69 with respect to the pawl 73.

The printing ribbon 45 is provided with a metal eyelet 84 near each of its ends. As the ribbon becomes nearly exhausted on the reel 29, the eyelet 84 engages a pair of studs 85 `and 86 provided on a lever 87 pivoted on a stud shaft 88 of the base casting 38. The next few feed steps of the ribbon 45 cause the eylet 84 to move the lever 87 clockwise as seen in FIG. 4, the angular movement of the lever being eventually completed by an overcenter spring 89 having one end anchored on a pin 90 of the casting 38 and having its other end anchored on a pin 91 of the lever 87. The lever S7 also has a pair of studs 85 and 86 at its lower end for engagement with the eyelet (not shown) provided at the other end of the ribbon 45 to effect counterclockwise movement of the lever 87 when the ribbon, while feeding from the reel 30 to the reel 29, becomes nearly exhausted on the reel 30. These clockwise and counterclockwise movements of the lever 87 are limited 'by `a stop pin 92 provided on the lever 87 and engaging a U-shaped stop bracket 93 secured to the base casting 38. A yoke 94 is pivotally secured by a pin 95 to the lever 87 and has a cylindrical end 96 bored and internally threaded to receive the threaded end of a link rod 97. The latter is provided with a flattened and hooked end portion which is pivotally anchored in an aperture 98 of an anvil 99 supported for reciprocatory movement in a groove 100 provided in a guide member 101 secured by machine screws 102 to a stud 103 on the base casting 38. The anvil 99 is retained in the groove 100 by a hold-down member 104 having a turned over end extending into a groove 105 of the anvil 99.

It will be apparent that angular movement of the lever 87 is transmitted by the link rod 97 to the anvil 99 to effect forward and backward motion of the latter. Assume by Way of example that, as illustrated in FIG. 6, the eyelet 84 has rotated the lever 87 sufficiently far that the overcenter spring 89 completes the clockwise movement to engage the stop pin 92 with the stop bracket 93. It will be evident that this movement of the lever 87 causes the anvil 99 to be correspondingly moved to the left to the position shown in FIG. 6. This movement is illustrated in FIG. 6 as having occurred at a time when the pawl 69 has been moved by the crank arm 66 to the end of its feed stroke. Now upon return of the pawl 69 from its feed stroke, a projection 106 provided on one side of the pawl 69 near its pivot 68 engages the upper surface 107 of the anvil. Continued counterclockwise drive of the bell crank 66 forces the pawl 69 to be moved counterclockwise about its pivot 68 and thereby effect engagement of its bevelled end 70 with the teeth of the ratchet wheel 43 as shown in FIG. 7. This angular movement of the pawl 69 is transmitted by the helical springs 77 and 78 to the detent pawl 73 to cause the latter also to move counterclockwise, whereby its bevelled end S3 also engages the teeth of the ratchet wheel 43 as shown in FIG. 7. The ribbon feed is thereupon changed from the ratchet wheel 44 to the ratchet wheel 43, and the ribbon 45 now feeds from the reel 30 to the reel 29. When the lever 87 is eventually moved counterclockwise by engagement of the ribbon eyelet with the studs 85 and 86 as previously explained, the anvil 99 is moved to the right as seen in FIGS. 4-7. Upon completion of the next feed stroke of the pawl 69, a projection 108 provided on the side of the feed pawl 69 opposite the projection 106 engages the upper surface 109 of the anvil 99. Further counterclockwise drive of the bell crank 66 forces the pawl 69 to move clockwise about its pivot 68, and this effects restoration of the pawls 69 and 73 to the positions shown in FIGS. 4 and 6 where their respective beveled ends 70 and 83 engage the teeth of the ratchet wheel 44. The ribbon 45 now feeds from the supply reel 29 to the supply reel 30.

It will be apparent from the foregoing description of the invention that a ribbon feed mechanism embodying the invention has a relatively sturdy yet low cost construction and provides a very reliable character of automatically reversible ribbon feed operation needing minimum care and attention over prolonged operational periods.

While a specific form of invention has been described for purposes of illustration, it is contemplated that numerous changes may be made without departing from the spirit of the invention.

What is claimed is:

1. A print ribbon feed mechanism for a character printer comprising, a pair of ribbon reels rotatably supported with associated drive ratchet wheels in adjacent but spaced positions, means for guiding a print ribbon for movement between said reels and past a character-print zone, a pawl pivotally supported on an arm of a rotatably supported bell crank for reciprocal motion with relation to a pivoted detent member resiliently coupled thereto to move angularly therewith between two angular positions in individual ones of which said pawl and detent member are based to engage the teeth of an individual one of said ratchet wheels, means responsive to each character printing operation for angularly reciprocating said bell crank to reciprocate said pawl and rotatably drive the one of said ratchet wheels engaged thereby, whereby said print ribbon is moved by successive-step motion past said print zone and from the then idle to the then driven one of said reels, said pawl having oppositely disposed projections at the region of the pivot point thereof, a longitudinally movable anvil member having anvil portions selectively engageable with individual ones of the project1ons on said pawl, and means responsive to each state of near exhaustion of a supply of ribbon on the then idle one of said reels for longitudinally moving said anvil member to engage an anvil portion thereof with a projection on said pawl and utilize the reciprocal drive of said pawl by said bell crank and said resilient coupling of said pawl with said detent member concurrently to pivot and engage both said pawl and detent member with the ratchet wheel of the reel previously idle to reverse the direction of step movement of said ribbon past said print zone and between said reels.

.2. A print ribbon feed mechanism for a character printer comprising, a pair of ribbon reels rotatably supported with associated drive ratchet wheels in adjacent but spaced positions, means for guiding a print ribbon jfor movement between said reels and past a characterprint zone, a pawl pivotally supported on an arm of a rotatably supported bell crank for reciprocal motion with angular movement of said bell crank and for angular motion about its pivot point between two angular positions in individual ones of which said pawl is biased by an overcenter spring to engage the teeth of an individual one of said ratchet wheels, a pivoted detent member spring coupled to said pawl to be angularly moved thereby to two positions in which said detent member also is biased by said spring coupling into engagement with the teeth of the same ratchet wheel as is engaged by said pawl, means responsive to each character printing operation for angularly reciprocating said bell crank to reciprocate said pawl and rotatably drive the one of said ratchet wheels engaged thereby, whereby said print ribbon is moved by successivestep motion past said print zone and from the then idle to the then driven one of said reels, said pawl having oppositely disposed and spaced-apart projections at the region of the pivot point thereof, a longitudinally movable anvil member having spaced-apart anvil portions selectively engageable with individual ones of the projections on said pawl, and a member mechanically coupled to said anvil member and biased by an overcenter spring for snapaction angular movement between two positions in response to each state of near exhaustion of a supply of ribbon on the then idle one of said reels for longitudinally reciprocating said anvil member between two positions to engage an anvil portion thereof with a projection on said pawl and utilize the reciprocal drive of said pawl by said bell crank concurrently to pivot and engage both said pawl and detent member with the ratchet wheel ofthe reel previously idle and thereby reverse the direction of step movement of said ribbon past said print zone and between said reels.

3. A print ribbon feed mechanism for a character printer comprising, a pair of ribbon reels rotatably supported with associated drive ratchet wheels in adjacent but spaced positions, means for guiding a print ribbon for movement between said reels and past a character-print zone, said ribbon having a metallic insert near each end to indicate the approach of a corresponding end of the ribbon, a pawl pivotally supported for reciprocal motion with relation to a pivoted detent member resiliently coupled thereto to move angularly therewith between two angular positions in individual ones of which said pawl and detent member are biased to engage the teeth of an individual one of said ratchet wheels, means responsive to each character printing operation for reciprocating said pawl rotatably to drive the one of said ratchet wheels engaged thereby and move said print ribbon by successivestep motion past said print zone and from the then idle to the then driven one of said reels, a reciprocal anvil member having two anvil portions engageable by individual ones of two projections provided on said pawl on opposite sides of and substantially aligned with the pivot point thereof, and means engaged by said ribbon inserts and actuated by continued ribbon movement for moving said anvil member to engage an anvil portion with one of said pawl projections and utilize the succeeding reciprocal motion of said pawl and its resilient coupling with said detent member concurrently to pivot and engage both said pawl and detent member with the ratchet wheel of the reel previously idle to reverse the direction of step movement of said ribbon past said print zone and between said reels.

4. A print ribbon feed mechanism for a character printer comprising, a pair of ribbon reels rotatably supported with associated drive ratchet wheels in adjacent but spaced positions, means for guiding a print ribbon for movement between said reels and past a character-print zone, said ribbon having an eyelet insert near each end to indicate the approach of a corresponding end of the ribbon, a pawl pivotally supported on an arm of a rotatably supported bell crank for reciprocal motion with relation to a pivoted detent member resiliently coupled by oppositely disposed helical springs to said pawl to move angularly therewith between two angular positions in individual ones of which said pawl and detent member are biased by an over-center spring to engage the teeth of an individual one of said ratchet wheels, means responsive to each character printing operation for angularly reciprocating said bell crank to reciprocate said pawl and rotatably drive the one of said ratchet wheels engaged thereby, whereby said print ribbon is moved by successive-step motion past said print zone and from the then idle to the then driven one of said reels, an anvil member movable selectively to two positions in which an individual one of two anvil portions is engaged by individual ones of two ,projections provided on said pawl and effective upon such engagement to move said pawl angularly about its pivot point to individual ones of said two angular positions thereof, a pivotally supported feed-control member having arms engaged by individual ones of said ribbon inserts and angularly moved in individual angular directions by continued ribbon movement, and a mechanical connection between said feed-control member and said anvil member for positioning said anvil member with movement of said feed-control member to utilize the reciprocal drive of said pawl by said bell crank and said resilient coupling of said pawl with said detent member concurrently to pivot and engage both said pawl and detent member with the ratchet wheel of the reel previously idle to reverse the direction` of step movement of said ribbon past said print zone and between said reels.

References Cited in the file of this patent UNITED STATES PATENTS 1,937,145 Gollwitzer Nov. 28, 1933 2,505,991 Reinhold May 2, o 2,691,342 ,Johnston et al, T a, Oct. l2, 1954 

